1. Technical Field
This invention relates to active noise control, and more specifically to active noise control using at least one infinite impulse response filter.
2. Related Art
Active noise control may be used to generate sound waves that destructively interfere with a targeted undesired sound. The destructively interfering sound waves may be produced through a loudspeaker to combine with the targeted undesired sound.
An active noise control system generally includes at least one adaptive finite impulse response (FIR) filter. FIR filters are typically used due to low incidence of system instability. FIR filters generally display longer convergence times as compared to infinite impulse response (IIR) filters. While IIR filters may provide lower convergence times as compared to FIR filters, use of IIR filters may result in more instances of system instability. Therefore, a need exists to control IIR filter stability in active noise control systems.